We all know that fitting steel braided brake lines helps improve the feel and performance of brakes, but why is this? Brake lines on your motorcycle generally run at around 750psi and while rubber ones will pop at around 8,000psi, steel can resist up to 20,000psi – not that you are likely to ever get anywhere near this pressure figure.
So why do rubber lines feel different? Even from new, a rubber brake line will 'bell' or expand slightly under pressure. While this is initially very minimal, as the line ages the belling increases and with it the direct feel of the brake on you motorcycle is lost.
Steel braided brake lines do not allow the line to expand at all and so will deliver a constant and very direct braking feel on your motorcycle. Overall braking performance is hardly affected, but the feel is different. Additional to steel braided brake lines you should replace your brake fluid in time as instructed in your motorcycle manual. Brake fluid is hygroscopic, which means that it absorbing moisture from the atmosphere. Moisture absorbed by your brake fluid also makes your brakes feel spongy.
So now you know that losing braking power/feel is not always related to your brake pads, motorcycle manufacturers have a budget for parts they use to build your motorcycle, and this parts, including your brake lines and brake fluid, are often not the best money can buy. So think about that the next time you want to buy some modify / aftermarket parts for your motorcycle.